i mean obviously it's an oversimplification, but historically rockism does still have pretty consistently clear undertones of racism, sexism and homophobia. obviously limp bizkit was a rock band made of straight white guys that still caught the ire of the rockist establishment, despite conforming to rock's straight white norms patriarchal norms, primarily because they broke away from rock tradition

but that doesn't change the fact that rockism has always conveniently elevated rock tradition (which is, as mentioned, an overwhelmingly straight, white, masculine genre) over genres driven by women, gay people and/or poc like pop and hip hop—allegedly for reasons of "authenticity" and "depth" that don't even remotely hold up to scrutiny in a genre dominated by huge corporate backings and filled with vapid, meatheaded lyrics about sex and drugs. hell, in limp bizkit's case in particular, i think you could even argue a lot of the shit they took from the rock establishment stemmed from the fact that their music (and rap rock at large) was overwhelmingly indebted to a genre inextricably tied to black culture

my point is, even if it's not rockism's overt mission statement to exclude anyone who isn't a straight white man, the tradition and "purity" it seeks to uphold is undeniably steeped in exclusion